Stereotype plate



Aprfiil 211, 193% G. H. FULLER zmwm STEREOTYPE PLATE Filed May 9, 1931 INVEN TOR.

A TTORNEY. ,5

Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE STEREOTYPE PLATE Application May 9, 1931, Serial No. 536,135

1 Claim.

This invention relates to curved stereotype plates of the sort commonly used on modern high speed newspaper presses and to apparatus for making them. This invention aims to provide a plate of this character which is stronger than those now in use, both by reason of being re.- enforced against longitudinal distortion, and by reason of certain advantages in casting.

In the usual type of hollow semi-cylindrical stereotype plates a problem arises in connection with the present tendency toward increasing press speeds, the problem being to clamp the plate to the press cylinder tight enough to prevent creeping circumferentially under heavy impressions, but at the same time to prevent longitudinal distortion of the plate. The tendency to creep is particularly troublesome at high speeds and in making quick stops, and has therefore presented an increasingly difficult problem with the newest press developments.

The usual method of holding the stereotype plate on a press cylinder, as well known in the art, is by means of clamping rings and clamping lugs at the ends, and these must be set up with increasing tightness for the higher rotative speeds, but of course not tightly enough to distort the plate. It is customary to reenforce stereotype plates with circumferential ribs on the inner surface, but it has not hitherto been regarded necessary or possible to provide reenforcement extending longitudinally.

Although the present invention may be carried out in a variety of forms, I have herein shown a preferred embodiment and certain alternative constructions, it being understood, however, that these are illustrations of the invention and not limitations thereon.

In the accompanying drawing, Fig. 1 illustrates the mold cylinder of an automatic stereotype casting machine, modifiedin accordance with my invention. Fig. 2 illustrates a stereotype plate as made by such a mold. Figs. 3, 4, 5 and 6 are the back views in fiat development of various rib arrangements in accordance with my invention, Fig. 4 being the particular form shown in Fig. 2. Fig. '7 is an enlargement of a portion of Fig. 4, and Fig. 8 is a cross section showing rib form and spacing.

Referring now to Fig. 1, the mold cylinder III is illustrated as having a series of diagonal grooves II in addition to the usual circumferential grooves l2. A plate 13 as cast thereon will, consequently, have on its inner surface a corresponding series of diagonal ridges [4 in addition to the usual circumferential ridges I5, these ridges being more clearly shown in Fig. 7, wherein it will be observed that the inclination of the ridges I4 is such as to give a greater component longitudinally than circumferentially.

Figs. 3, 4, 5 and 6 illustrate various possible rib arrangements. It will be noted that Figs. 1, 2 and 7 are based upon the form shown in Fig. 4, which is the form I now regard as preferable.

In Fig. 3 a stereotype plate is illustrated which is provided with oppositely inclined series of ribs 14 and 16 in addition to the usual circumferential ribs 15.

In Fig. 5 one series of diagonal ribs I4 is shown in conjunction with a single longitudinal rib II. In Fig. 6 the diagonal ribs are omitted and short parallel ribs I8 and I9 are shown in successive staggered series.

In casting the plates the transverse mold grooves l2 which form the ribs [5 also serve to vent the longitudinal grooves in the mold. In the known practice of casting against a mold cylinder as shown in Fig. 1 there is a tendency for the upper part of the plate and for the upper transverse reenforcing ribs to be spongy, which of course is objectionable both from the standpoint of weakness and of giving the plate an imperfect face. In order to reduce the porosity of the upper part of the plate it is usual to fill the mold to a height considerably above the upper edge of the finished plate, well up onto the upper blank surface shown in Fig. 1, such excess metal being afterwards cut off. This has the disadvantage of requiring the handling of an amount of metal otherwise unnecessary, but even so is unsatisfactory and ineffectual to avoid the sponginess. It is apparent that this sponginess is due to gas bubbles being entrapped in the circumferential grooves 12 which form the ribs l5. Any series of grooves in the mold having an upward tendency, such as the grooves l l or grooves such as those which would be necessary to form ribs I! or l8, will provide a series of natural vent channels for the gases which bubble out of the molten metal in casting. Therefore, the grooves serve the two-fold purpose of making a plate back formation which is strengthened to recess the end thrust of the cylinder clamps and also make a more solid casting.

The above described reenforcement arrangements illustrate certain forms in which I have applied my invention, but are not to be taken as limitations upon the principle thereof, the scope and principle being indicated by the following claims.

What I claim is:

A curved stereotype plate having a plurality of series of reinforcing ribs on. the back thereof, the ribs of one series being positioned circumferentially of the plate and parallel to each other, while the ribs of the other series are parallel to each other and extend from one side to an adjacent side of the plate.

GEORGE H. FULLER. 

